Step 1: General equation of an ellipse.
The general equation of an ellipse with semi-major axis \( a \) and semi-minor axis \( b \) is:
\[
\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1
\]
Step 2: Formula for the area of an ellipse.
The formula for the area of an ellipse is given by:
\[
\text{Area} = \pi \times a \times b
\]
where \( a \) is the length of the semi-major axis and \( b \) is the length of the semi-minor axis.
Step 3: Applying the formula.
In this case, the equation of the ellipse is given, and we can directly apply the formula for the area. Substituting the values of \( a \) and \( b \) from the equation:
\[
\text{Area} = \pi \times a \times b
\]
Step 4: Conclusion.
Therefore, the area of the region bounded by the ellipse is \( \pi ab \) square units, and the correct answer is option (A).